void main(List<String> args){
  Student stu=Student(name:"张三",age:18);
  stu.song(stu.name!, stu.age!);
  Teacher tea=Teacher(name:"李四",age:30);
  tea.song(tea.name!, tea.age!);

}
//定义一个混入对象
mixin Base{
  void song(String name,int age){
    print("姓名：$name,年龄：$age 在唱歌");
  }
}
class Student with Base{
  String? name;
  int? age;
  Student({this.name,this.age});
}

class Teacher with Base{
  String? name;
  int? age;
  Teacher({this.name,this.age});
}
